<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<script type="text/javascript">
			var str="abc@abc.com.cn";
			reg=/^\w{3,}(\.\w+)*@[A-z0-9]+(\.[A-z]{2,5}){1,2}$/
			console.log(reg.test(str));
		</script>
	</head>
	<body>
	</body>
</html>